JAJSNU3 December   2023 AFE782H1 , AFE882H1

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics
    6. 5.6  Timing Requirements
    7. 5.7  Timing Diagrams
    8. 5.8  Typical Characteristics: VOUT DAC
    9. 5.9  Typical Characteristics: ADC
    10. 5.10 Typical Characteristics: Reference
    11. 5.11 Typical Characteristics: HART Modem
    12. 5.12 Typical Characteristics: Power Supply
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Digital-to-Analog Converter (DAC) Overview
        1. 6.3.1.1 DAC Resistor String
        2. 6.3.1.2 DAC Buffer Amplifier
        3. 6.3.1.3 DAC Transfer Function
        4. 6.3.1.4 DAC Gain and Offset Calibration
        5. 6.3.1.5 Programmable Slew Rate
        6. 6.3.1.6 DAC Register Structure and CLEAR State
      2. 6.3.2  Analog-to-Digital Converter (ADC) Overview
        1. 6.3.2.1 ADC Operation
        2. 6.3.2.2 ADC Custom Channel Sequencer
        3. 6.3.2.3 ADC Synchronization
        4. 6.3.2.4 ADC Offset Calibration
        5. 6.3.2.5 External Monitoring Inputs
        6. 6.3.2.6 Temperature Sensor
        7. 6.3.2.7 Self-Diagnostic Multiplexer
        8. 6.3.2.8 ADC Bypass
      3. 6.3.3  Programmable Out-of-Range Alarms
        1. 6.3.3.1 Alarm-Based Interrupts
        2. 6.3.3.2 Alarm Action Configuration Register
        3. 6.3.3.3 Alarm Voltage Generator
        4. 6.3.3.4 Temperature Sensor Alarm Function
        5. 6.3.3.5 Internal Reference Alarm Function
        6. 6.3.3.6 ADC Alarm Function
        7. 6.3.3.7 Fault Detection
      4. 6.3.4  IRQ
      5. 6.3.5  HART Interface
        1. 6.3.5.1  FIFO Buffers
          1. 6.3.5.1.1 FIFO Buffer Access
          2. 6.3.5.1.2 FIFO Buffer Flags
        2. 6.3.5.2  HART Modulator
        3. 6.3.5.3  HART Demodulator
        4. 6.3.5.4  HART Modem Modes
          1. 6.3.5.4.1 Half-Duplex Mode
          2. 6.3.5.4.2 Full-Duplex Mode
        5. 6.3.5.5  HART Modulation and Demodulation Arbitration
          1. 6.3.5.5.1 HART Receive Mode
          2. 6.3.5.5.2 HART Transmit Mode
        6. 6.3.5.6  HART Modulator Timing and Preamble Requirements
        7. 6.3.5.7  HART Demodulator Timing and Preamble Requirements
        8. 6.3.5.8  IRQ Configuration for HART Communication
        9. 6.3.5.9  HART Communication Using the SPI
        10. 6.3.5.10 HART Communication Using UART
        11. 6.3.5.11 Memory Built-In Self-Test (MBIST)
      6. 6.3.6  Internal Reference
      7. 6.3.7  Integrated Precision Oscillator
      8. 6.3.8  Precision Oscillator Diagnostics
      9. 6.3.9  One-Time Programmable (OTP) Memory
      10. 6.3.10 GPIO
      11. 6.3.11 Timer
      12. 6.3.12 Unique Chip Identifier (ID)
      13. 6.3.13 Scratch Pad Register
    4. 6.4 Device Functional Modes
      1. 6.4.1 DAC Power-Down Mode
      2. 6.4.2 Register Built-In Self-Test (RBIST)
      3. 6.4.3 Reset
    5. 6.5 Programming
      1. 6.5.1 Communication Setup
        1. 6.5.1.1 SPI Mode
        2. 6.5.1.2 UART Mode
        3. 6.5.1.3 SPI Plus UART Mode
        4. 6.5.1.4 HART Functionality Setup Options
      2. 6.5.2 GPIO Programming
      3. 6.5.3 Serial Peripheral Interface (SPI)
        1. 6.5.3.1 SPI Frame Definition
        2. 6.5.3.2 SPI Read and Write
        3. 6.5.3.3 Frame Error Checking
        4. 6.5.3.4 Synchronization
      4. 6.5.4 UART Interface
        1. 6.5.4.1 UART Break Mode (UBM)
          1. 6.5.4.1.1 Interface With FIFO Buffers and Register Map
      5. 6.5.5 Status Bits
      6. 6.5.6 Watchdog Timer
  8. 7 Register Maps
    1. 7.1 AFEx82H1 Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Multichannel Configuration
    2. 8.2 Typical Application
      1. 8.2.1 4-mA to 20-mA Current Transmitter
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Current Loop Control
          2. 8.2.1.2.2 HART Connections
          3. 8.2.1.2.3 Input Protection and Rectification
          4. 8.2.1.2.4 System Current Budget
        3. 8.2.1.3 Application Curves
    3. 8.3 Initialization Setup
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 ドキュメントの更新通知を受け取る方法
    3. 9.3 サポート・リソース
    4. 9.4 Trademarks
    5. 9.5 静電気放電に関する注意事項
    6. 9.6 用語集
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

6.4.3 Reset

There are three reset mechanisms in the device: a power-on reset (POR), a RESET pin, and the SW_RST command that can be sent through the either the SPI or by UBM.

When power is first applied to the device, a POR circuit holds the device in reset until all supplies reach the specified operating voltages. The power-on reset returns the device to a known operating state in case a brownout event occurs (when the supplies have dipped below the minimum operating voltages). The POR starts all digital circuits in reset as the supply settles, and releases them to make sure that the device starts in the default condition and loads the OTP memory. After the OTP memory has been loaded, the ALARM pin is released. At this time, communication with the device is safe. This tPOR time is less than 100 µs.

The devices also have a RESET pin that is used as a hardware reset to the device. Send the RESET pin low for a minimum of 100 ns (tRESET) to reset the device. A delay time of 10 μs (tRESETWAIT) is required before sending the first serial interface command as the device latches and releases the reset. The release of the internal reset state is synchronized to the internal clock. The RESET pin resets the SPI and the UART interfaces, the HART FIFO buffer, the watchdog timer, the internal oscillator, and the device registers. RESET does not reload the OTP memory.

The command to RESET.SW_RST = 0xAD resets the device as a software reset. The command is decoded at the rising edge of CS with an SPI command or during the stop bit of the last character of a UBM frame. Set UBM.REG_MODE again to put the device back into UBM when resetting the device in UBM. After sending the RESET command, no delay time is required before sending the first serial interface command as the device latches and releases the reset. The reset is synchronized to the falling edge of the internal clock and is released well before the next rising edge. The ALARM pin pulses low for the width of the internal reset. This pulse duration is less than 20 ns. This command resets the SPI and the UART interface, the HART FIFO, and the watchdog timer, but does not reset the internal oscillator. The software reset also reloads internal factory trim registers if properly configured in the SPECIAL_CFG register. The SPECIAL_CFG register is only reset with a POR.

The POR and hardware reset place the internal oscillator into a reset condition, which holds the clock low. When these two signals are released, there is a delay of a few microseconds before the first rising edge of the clock. The hardware reset, RESET, pulse width must be at least 100 ns to allow the oscillator to properly reset. The SW_RST command is a short pulse. This pulse is not long enough to adequately reset the oscillator. The SW_RST is asserted with a falling edge of the clock. As a result of the long oscillator period, the design architecture provides that all devices are out of reset by the next rising edge.

Figure 6-25 shows the reset tree.

GUID-20210713-CA0I-LKBC-PQZ2-CZVX9WW3MDDM-low.svg Figure 6-25 Reset Conditions